Played through the first 4 levels last night. The game is pretty darn fun.

My only gripe with the game are the Naga levels. The controls on those levels are just ass. But pretty much that is my only issue with the game.
Otherwise the voice acting and style of the game are pretty on par with the show, and it is actually a lot of fun playing as The Avatar.
If you are a fan of the show I would highly recommend picking up a copy.